1. Field of the Invention
The present invention in related to a fluid processing method of an object to be processed and an apparatus thereof required for the manufacturing process of thin film devices. In particular, the present invention is related to a fluid processing method of an object to be processed and an apparatus thereof suitable for a semiconductor manufacturing process that demands an extremely clean environment.
2. Description of the Related Art
In recent years miniaturization of the structure of thin film devices such as semiconductors, liquid crystal displays and magnetic disks has been progressing and because of the performance of these devices and improved manufacturing yield rates, this is followed by expectations of extremely clean manufacturing processes. Looking at a semiconductor wafer as an example, the size of the foreign matter to be removed for a wafer of 0.2 um or more should be 10 parts or less per wafer, the amount of contaminants of metal ions should be 10.sup.10 atoms/cm.sup.2 or less, and the thickness of the oxide film formed by contact with air should be 1 nm or less.
Furthermore, the mixed production of multiple types of products become unavoidable making necessary equipment that can work with numerous manufacturing processes while putting sheet processing methods which process a plate-shaped object to be processed (hereinafter referred to as simply object to be processed) one wafer at a time.
As a first conventional example, FIG. 7 shows a substrate process of Japanese Patent Laid-open No. 08-316190. In this conventional example, a plate-shaped object to be processed 53 is fixed to a substrate retention member 54 and also rotates (rotation means not shown in the figure). In order to prevent the front surface of the object to be processed from becoming contaminated due to the turbulent flow produced by the rotation of the plate-shaped object to be processed 53, the front surface of the plate-shaped object to be processed 53 is covered by a shielding plate 52 (hereinafter referred to front shielding plate) and a fluid process is carried out in which process fluid is injected onto the front surface of the plate-shaped object to be processed 53 only by means of a pure water injection nozzle 51. In this first conventional example, because a shielding plate (hereinafter referred to rear shielding plate) is not provided on the rear surface of the plate-shaped object to be processed 53, the following problems occurred.
In addition to the fact that there was no fluid processing of the rear surface, the rear surface of the object to be processed became contaminated due to the turbulent flow generated by the rear surface of the plate-shaped object to be processed 53. When the rear surface of the object to be processed becomes contaminated, in processes after that the front surfaces of apparatuses such as a transfer arm for the object to be processed that makes contact with the rear surface of the object to be processed and a retention member for the object to be processed (not shown in the figure) undergo transfer contamination and the rear surface of the object to be processed after that becomes even more contaminated reducing the quality of the product. In particular, in processes which are subjected to heat, contaminants developed which were adhering to the rear surface of the object to be processed, reaching the front surface of the object to be processed which in turn caused fatal contamination on the front surface of the object to be processed.
As a second conventional example that can solve this problem, FIG. 8 shows a processing method of work and apparatus of Japanese Patent Laid-open No.08-78368. In this conventional example, the rear surface of the object to be processed is also covered by a rear shielding plate 62 to prevent the rear surface of the object to be processed from becoming contaminated due to the above-mentioned turbulent flow along with the front and rear surfaces of the object to be processed undergoing fluid processing simultaneously.
However, the object to be processed 64 in this example must be rotated in order to carry out uniform fluid processing on the front surface of the object to be processed. Considering this point, a retention means of the object to be processed 64 is mechanically provided integrally on the rear shielding plate 62 in this second conventional example and the object to be processed 64 and the rear shielding plate 62 are rotated simultaneously with a motor 65. The fluid is supplied from a supply tank 74 and is then switched by three-way valves 67, 68 and diverted to front shielding plate 61 and rear shielding plate 62. Although the connection structure of a supply pipe 76 to the rear shielding plate 62 is not mentioned in the second conventional example, the one rear shielding plate 62 rotates and the other supply pipe 76 is normally fixed. Further, the symbol 70 is a fresh fluid supply portion.